plotter is an empirical plotting tool to draw curves of mathematical expressions (usually these will be functions) as images (in gif, jpeg or png format). Currently, plotter draws up to 3 curves in cartesian coordinates and can do a bit of differential calculus. Here's an example of a plotter-created curve on github.io.
The images can be drawn on the fly: after the desired plot is created and formatted in the UI part, plotter creates an URL (a really ugly one with a ridiculously long query string containing all required options). The plot will then be recreated whenever this URL is called - copy the URL into the src-attribute of an image-tag to use a dynamically created plot on every page load.
To run a plotter, a standard installation of a webserver capable of interpreting PHP (>=4.3 - that is untested) with an enabled GD extension is needed.
This project is published as open source licensed under the terms of the Gnu General Public License, version 2 (GNU GPL v.2) license.